Organocatalyzed Dearomative Cycloaddition of 2-Nitrobenzofurans and Isatin-Derived Morita-Baylis-Hillman Carbonates: Highly Stereoselective Construction of Cyclopenta[ b]benzofuran Scaffolds

Org Lett. 2019 Feb 1;21(3):660-664. doi: 10.1021/acs.orglett.8b03786. Epub 2019 Jan 14.

Abstract

The first organocatalyzed asymmetric dearomative cycloaddition between 2-nitrobenzofurans and isatin-derived Morita-Baylis-Hillman carbonates has been developed. Using a modified cinchona alkaloid as the catalyst, a series of structurally diverse cyclopenta[ b]benzofuran derivatives with three contiguous stereocenters, including a spiro-quaternary chiral center, could be smoothly obtained in excellent results (all cases >20:1 dr, up to 99% yield and 98% ee). The utility of this method was showcased by the versatile transformations of the product.

Publication types

  • Research Support, Non-U.S. Gov't